That happened to me yesteday.
An Iron supplement, 325 mg, 60 tablets, $2.49.
I had to ask the pharmacist for this, and it was filled in a nice little pharmacy bottle complete with child proof cap, and a pharmacy label, but no Rx number. And that $2.49 is not going to find its way to a Schedule A.
But if you have a healthcare reimbursement plan or an HSA plan you can almost certainly claim it there.
In general, you cannot include in your medical expenses the cost of a prescribed drug brought in (or ordered/ shipped) from another country. You can only include the cost of a drug that was imported legally. For example, you can include the cost of a prescribed drug the Food and Drug Administration announces can be legally imported by individuals.
You can include the cost of a prescribed drug you purchase and consume in another country if the drug is legal in both the other country and the United States.